— Feb. 14, 2015: A gunman kills Danish filmmaker Finn Noergaard and wounds three police officers in Copenhagen. A day later the gunman, Omar El-Hussein, attacks a synagogue, killing a Jewish guard and wounding two police officers before being shot dead.

— Jan. 7-9, 2015: A gun assault on the Paris offices of the satirical magazine Charlie Hebdo and an attack on a kosher grocery store kills 17 people. Al-Qaida in the Arabian Peninsula claims responsibility for the attack, saying it was in revenge for Charlie Hebdo’s depictions of the Prophet Muhammad.

— May 24, 2014: Four people are killed at the Jewish Museum in Brussels by an intruder with a Kalashnikov. The accused is a former French fighter linked to the Islamic State group in Syria.

— May 22, 2013: Two al-Qaida-inspired extremists run down British soldier Lee Rigby in a London street, then stab and hack him to death.

— March 2012: A gunman claiming links to al-Qaida kills three Jewish schoolchildren, a rabbi and three paratroopers in Toulouse, southern France.

— July 22, 2011: Anti-Muslim extremist Anders Behring Breivik plants a bomb in Oslo then launches a shooting massacre on a youth camp on Norway’s Utoya island, killing 77 people, many of them teenagers.

— Nov. 2, 2011: The offices of Charlie Hebdo in Paris are firebombed after the satirical magazine runs a cover featuring a caricature of the Prophet Muhammad. No one is injured.

— March 2, 2011: Islamic extremist Arid Uka shoots dead two U.S. airmen and injures two others at Frankfurt airport after apparently being inspired by a fake internet video purporting to show American atrocities in Afghanistan.

— July 7, 2005: 52 commuters are killed in London when four al Qaida-inspired suicide bombers blow themselves up on three subway trains and a bus.